I have to cut a couple of new heat sinks for 98s now that I have a TIG again. For the life of me I can't recall the geometry on the bolt shroud buttress thread. Is it 30 degree follow and 7 degree lead, or 45 degree follow and 7 degree lead? Or did they use a 90 degree lead?

I'm so confuzzled ! ! !

I make them 60/90 degrees, which is easy and they work. Don't have to be perfect. But if you don't know, then who on the planet does?

quote:

Originally posted by dpcd:
I make them 60/90 degrees, which is easy and they work. Don't have to be perfect. But if you don't know, then who on the planet does?

You mean 30 and 90, I guess? I think conventional Buttress is 7 degrees on the leading edge that does the work and 45 degrees on the trailing edge. I think Metric Buttress is different at 3 degree lead and 30 trailing.

But of course NOTHING that Paul Mauser did was conventional. The 98 was a bastard, mixed with 55 degree Whitworth, Buttress and numbers that don't really equate to fuck all. I think he would have made a good German engineer !

I'm probably overthinking something that I'm just going to burn all to shit? I need a forehead slap, maybe ? ! ? ! ? ! ?
But not a double windup, under handed, open handed, pee pee slap. Those hurt to much!

NUFF SAID !

98 Mauser Buttress Thread by Rod Henrickson, on Flickr

I don't know what the answer is, Rod, but am familiar with the problem. You should write a book. In getting it down for others you'll help remind yourself

quote:

Originally posted by sambarman338:
I don't know what the answer is, Rod, but am familiar with the problem. You should write a book. In getting it down for others you'll help remind yourself

I finally got out the BIG LENS and blasted the thread and measured the angles sambarman338. I searched the entire net and even asked the kids in the CST Alumni forum and they didn't know. I guess they don't teach Mauser in school anymore. I am sort of compiling everything in my posts and other wise.


Actually, Billy Leeper and I are both writing a book. We're copying over Duane Wiebes shoulder. So this could take time. Duanes getting pretty old and he takes a lot of nap breaks!

My grinding skills leave a lot to be desired....
Happily gave Brownell's $20 for it, lol.

Straight infeed as a form cutter I guess?

Rod.

Just which plant made the sleeve you took a pic of ??? AND WHEN ??

I have a copy of a factory Obendorf print ( 1942 ) that Hartman & Weiss gave me years ago to properly copy the Mauser threads, and rest of the sleeve.

Pitch, 2mm per thread
Flat Crest in bottom of thread, .35mm wide
Flat Crest on top of thread .35mm wide
Depth from flat crest to flat bottom .75mm tall
Angle of buttress 30 degrees
Back angle of buttress not speced out

AuBen ( outside diameter ) 13.5mm outside to top of crest
Kern ( minor diameter ) 12 mm from bottom flat to bottom flat.

BUT as I have reworked many different Mauser sleeves over the years, BOY OH BOY you can tell the differrence between plants and production times that made the parts.
AND the Pre WW1 parts are differrent yet, ( Much tighter and smaller dims ), than post WW1 parts.

I just redid a BUNCH of post WW2 FN sleeves and wow were the threads oversize, they would not screw into a 1909 bolt, I had to recut every one of their threads.

Just another 2 cents.

JW

The 33°/3° German (saw tooth) buttress thread jc

quote:

Originally posted by J Wisner:
Rod.

Just which plant made the sleeve you took a pic of ??? AND WHEN ??


JW

It's a Zastava M48 Jim. I did have some sort of ""OFFICIAL"" drawing for the Mauser buttress and somehow misplaced it. I do remember old, Gus Crites saying that nothing much with the bolt shroud threads was even close to a standard. Rudy VanOwen however, used to say that there were VERY standardized geometries in many different plants. Also, I have had many people who claim to be in the know of things say that it's actually 13 TPI which would fall in line with the use of English threads in other areas. Still others swear that its 2mm. There is only .002 inch difference, so over that length on a Buttress thread, as far as I'm concerned, it makes no difference.

The photo should be pretty accurate as I squared the lens to the bolt shroud with a parallel and kept the lens about 2 inches away to keep it from fish-eyeing. But of course the next one I check could be totally different. And it probably will be. LOL

I think the old axiom holds true in this case: "Gentlemen, I don't have to tell you that there is a war going on. That means we're on a time line and a budget and you could be up to your asses in the mud right now, instead of being here where it's warm and dry. MAKE IT WORK !"

ADD NOTE: This one seems to have about a .010 inch radius on the bottom and I suppose a corresponding .020 flat on the top. But it's pretty beat up.